JPS5921393Y2 - Development control device for electrostatic copying machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing unit of an electrostatic copying machine, and particularly to a device for regulating development so that toner does not adhere to areas of a photoreceptor that are unnecessary for image formation.

In an electrostatic copying machine, a photoreceptor is charged and exposed to form an electrostatic latent image corresponding to the document, and after this latent image is made visible by adhering toner in a developing section, it is transferred to this toner image as appropriate. There is a method that transfers the image onto transfer paper that is provided.

In this method, it is necessary to provide a means for peeling the transfer paper from the photoreceptor.

As this transfer paper peeling means, a peeling member is provided at a minute interval or in contact with the surface of the photoreceptor, the edge of the transfer paper is overlapped with this peeling member and the transfer paper is sent, and after transfer, the peeling member is removed from the photoreceptor. Since the transfer paper is formed in the opposite direction to the rotation direction, the transfer paper is forcibly separated from the photoreceptor from the edge.

Therefore, in the area of the photoreceptor that is in opposing contact with the peeling member,
When a toner image is formed, the peeling member may be stained and the edges of the transfer paper may be stained.

In order to prevent this, a means is required to prevent toner from adhering to the area of the photoreceptor.

Conventionally, there are two methods as the above-mentioned regulating means.

One is to control the charging of the photoreceptor, and the other is to control the development of the photoreceptor.

In the former method, a charge regulating member is provided at the end of the charger corresponding to the peeling member, and the area of the photoreceptor facing the peeling member is not charged, so that an electrostatic latent image is not formed in that area.

Although the latter does not regulate the charging of the photoreceptor, a regulating member is provided in the developing section to prevent toner from adhering to the area of the photoreceptor facing the peeling member.

As a specific example of this, for example, in the magnetic brush development method,
A regulating material is provided on the magnetic brush, and the regulating material prevents the brush from coming into contact with the non-developing area of the photoreceptor that faces the peeling member.

However, the above-mentioned charge control method cannot completely control the ion distribution by the charger, and charging is not performed uniformly near the boundary between the charged and non-charged areas, resulting in blurred images and adversely affecting copy quality. become.

In addition, in the development regulation method, one side of the film-like regulation member is simply applied to the brush, and the other side is brought into sliding contact with the photoreceptor, so that the edge of the photoreceptor, that is, the boundary between the developing area and the non-developing area, is In this case, the alignment or distribution of the brushes is disturbed, and due to the regulating member slidingly contacting the photoreceptor surface, toner is drawn into the non-development area (between the photoreceptor and the regulating member), and a linear toner image is formed at the boundary. resulting in unwanted copies.

The present invention relates to the latter and provides a very useful development regulating device that eliminates the above-mentioned drawbacks.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an example of a copying machine of the present invention, and FIG. 2 is a perspective view.

In the figure, reference numeral 1 denotes a corona charger, which uniformly charges the surface of the photoreceptor drum 2 to a constant polarity.

Reference numeral 3 denotes an exposure section on which a light image corresponding to the original is formed to form an electrostatic latent image on the surface of the photoreceptor.

Reference numeral 4 denotes a developing roller for applying toner to the latent image formed on the surface of the photoreceptor, and a magnetic brush 5 is formed around the developing roller.

Reference numeral 6 is a transfer paper peeling member that is interposed between the edge of the transfer paper 7 that is sent as appropriate and the photoreceptor drum 2, and is attached in a state in which it is in contact with the surface of the photoreceptor drum 2.

8 is a corona charger for transfer.

The peeling member 6 has a tip end curved in a direction opposite to the rotational direction of the photosensitive drum 1, and forcibly separates the transfer paper 7 that is in close contact with the surface of the photosensitive drum 1 from the edge.

In this case, it is undesirable for toner to adhere to the non-image area of the photoreceptor facing the peeling member 6.

In other words, if toner is attached, the toner is removed from the peeling member 6.
In addition, the edge of the transfer paper 7 superimposed on the peeling member 6 will also be soiled.

Therefore, in the present invention, as shown in the figure, a development regulating section 9 is provided on the developing roller 4 facing the non-developing area of the photoreceptor.

The development regulating section 9 consists of a regulating film 9-1 and a space film 9-2.
2 is formed smaller than the regulating film 9-1, and as shown in FIG. 3, the regulating film 9-1 and the photoreceptor are overlapped in a stepped manner so that there is a space between them.

The space film 9-2 is in sliding contact with the photoreceptor, and the regulating film 9-1 restricts the end of the magnetic brush 5 from coming into contact with the photoreceptor.

In the configuration of the regulating section 9 described above, by providing a space film 9-2 and forming a space between the regulating film 9-1 and the photoreceptor, the toner image is formed in the regulating section in the space after development. No contact with 9 and no rubbing.

Therefore, linear images such as toner trailing or staining do not occur at the boundary between the development area and the non-development area (non-image area).

Further, since the regulating portions 9 are uniformly provided along the surface of the photoreceptor at intervals of the space films 92, the image does not become blurred at these boundaries.

Further, the space film 9-2 comes into direct contact with the photoreceptor, but at this position, the developer of the magnetic brush 5 does not come into direct contact with the regulation film 9-1 due to the space, etc., so no toner image appears. .

The above space film 9-2 and regulation film 9-1
As the space formed by
mm (in contact with the photoreceptor drum), good copies without border lines could be obtained.

In the figure, reference numeral 10 indicates a toner image in which toner adheres to the latent image in the developing section, and reference numeral 10-1 indicates a state in which development is regulated in the development regulating section 9 and toner is attached in a semicircular shape.

Also, 11. is a peeling roller that bites into the forcibly peeled edge and sends it to the next fixing process.

As explained above, in the development regulating device of the present invention, the regulating portion is composed of a regulating member and a space member that provides a stepped space between the regulating member and the photoreceptor. Therefore, by providing this regulating portion, it is possible to obtain a good copy without forming a linear toner image on the boundary surface.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional view and a perspective view showing an example of a copying machine according to the present invention, and FIG. 3 is a cross-sectional view for explaining a development regulating section according to the present invention. 2; Photosensitive drum, 4; Developing roller, 9; Development regulating section,
9-1; Regulatory film; 9-2; Space film; s, d; interval and width of stepped space.

Claims (1)

[Scope of utility model registration request] In a development regulating device having a toner adhesion regulating member located in a developing section that develops an electrostatic latent image and in close contact with a photoreceptor facing a non-development area, the toner adhesion regulating member is arranged so as to correspond to the non-development area. and a space member interposed between the regulating member and the photoreceptor and forming a stepped space between the regulating member and the photoreceptor at the end of the regulating member. Development control device for electrostatic copying machines.